• Epidemiology
  1. Incidence: 170 per 100,000 persons/year
  2. Ages 10 to 50 years (peaks age 20 to 30 years)
  3. No gender predisposition
  4. Seasonal variation: more common in spring and fall
  5. Higher risk in pregnancy (RR 3)
    1. Associated with increased Miscarriage rate before 15 weeks gestation (see below)
  • Pathophysiology
  1. Papulosquamous eruption
  2. Thought to be of infectious etiology (Viral Exanthem)
    1. May be associated with reactivation of Human Herpes Virus 6 (Roseola Infantum, HHV-6) or HHV-7
    2. Campolat (2009) J Eur Acad Dermatol Venereol 23(1): 16-21 [PubMed]
  • Symptoms
  1. Moderate to Severe Pruritus (25-50% of cases)
    1. Especially in children
  2. Other symptoms present in only 5% of patients
  3. Viral prodrome-type constitutional symptoms may occur with mild URI symptoms
    1. Headache
    2. Malaise
    3. Arthralgias
    4. Chills
  4. Nervousness
  5. Gastrointestinal symptoms
    1. Vomiting
    2. Diarrhea or Constipation
  • Signs
  1. Herald Patch (initial presenting lesion in 80-90% of patients)
    1. Single oval Macule or patch on trunk
    2. Diameter: 2 to 10 cm
    3. Characteristics: Annular Lesion (oval)
      1. Erythematous (rose colored) border with fine peripheral scale
      2. Central clearing
  2. Christmas tree pattern rash
    1. Onset occurs 7-14 days after herald patch
    2. Lesions may continue to appear for up to 6 weeks after onset
    3. Symmetric bilaterally
    4. Smaller than herald patch (<1 cm)
    5. Rash follows skin Cleavage Lines (Langer Lines)
      1. Christmas-Tree distribution on back
      2. V-Shaped distribution on the chest
    6. Individual lesions appear similar to herald patch
      1. Small fawn or salmon colored oval Macules
      2. Peripheral scaly collarettes
      3. Central clearing
  3. Darker skin: Black Children
    1. More facial (30% of cases) and scalp involvement
    2. Post-inflammatory pigment changes take place in nearly two thirds of patients
  4. Variants: Atypical Pityriasis Rosea
    1. Pityriasis Rosea Gigantea of Darier
      1. Fewer, but larger lesions
    2. Inverse Pityriasis Rosea
      1. Lesions primarily involve face, axilla, groin
    3. Pityriasis Rosea of Vidal
      1. Large patches involve the axillae or inguinal region
  • Differential Diagnosis
  • Medical Conditions
  1. See Annular Lesion
  2. Viral Exanthem
  3. Seborrheic Dermatitis
  4. Secondary Syphilis
    1. Unlike pityriasis, Syphilis affects palms and soles
  5. Nummular Eczema
  6. Tinea Corporis
    1. Typically a single lesion (may be confused with herald patch)
    2. Once Christmas Tree pattern of lesions develops, Pityriasis diagnosis becomes more obvious
  7. Guttate Psoriasis
  8. Lichen Planus
  • Associated Conditions
  • Medications associated with Pityriasis Rosea Eruptions
  1. Adalimumab (Humira)
  2. Allopurinol
  3. Arsenic
  4. Asenaprine
  5. Atenolol
  6. Barbiturates
  7. BCG vaccine
  8. Bismuth
  9. Bupropion
  10. Captopril
  11. Clonidine
  12. Clozapine
  13. Ergotamine
  14. Gold
  15. Hepatitis B Vaccine
  16. Imatinib (Gleevec)
  17. Interferon alfa
  18. Influenza Vaccine
  19. Isotretinoin
  20. Ketotifen
  21. Lamotrigine (Lamictal)
  22. Lisinopril
  23. Nortriptyline
  24. Omeprazole (Prilosec)
  25. Pneumovax Vaccine
  26. Rituximab
  27. Smallpox Vaccine
  28. Terbinafine
  29. Yellow Fever Vaccine
  • Labs
  1. Syphilis Serology (RPR)
  2. Skin biopsy for direct fluorescent Antibody
    1. Indicated only if Syphilis strongly considered
    2. Pityriasis Rosea will show dyskeratotic degeneration
  • Management (No effective treatment)
  1. Severe Pruritus
    1. See Pruritus Management
    2. Topical Corticosteroid
    3. Oral Antihistamine
    4. Calamine lotion or Zinc Oxide
  2. Severe Cases
    1. Ultraviolet A Light
    2. Ultraviolet B Light
    3. Systemic Corticosteroids
    4. Acyclovir
      1. Adult standard dosing: 800 mg orally five times daily for 7 days (400 mg may also be effective)
  3. Disproven treatments
    1. Macrolides (e.g. Erythromycin) are now not thought to be effective
  • Complications
  1. Associated with Miscarriage (57%) when presents in the first 15 weeks of pregnancy
    1. Drago (2014) J Am Acad Dermatol 71(1): 198-99 [PubMed]
  • Course
  1. Spontaneous resolution within 6 to 8 weeks in 80% cases (range 2-12 weeks duration)
  2. Recurrence in less than 3%
  • References
  1. Allen (1995) Cutis 56:198-202 [PubMed]
  2. Allmon (2015) Am Fam Physician 92(3): 211-6 [PubMed]
  3. Chuh (2016) J Eur Acad Dermatol Venereol 30(10): 1670-81 [PubMed]
  4. Hsu (2001) Am Fam Physician 64(2):289-96 [PubMed]
  5. Kempf (2000) Arch Virol 154(8):1509-20 [PubMed]
  6. Stulberg (2004) Am Fam Physician 69:97-94 [PubMed]